“Whence one hath wobbled, is it not thenceforth a foregone conclusion that one shall, before a fortnight hath passed, fall down on one's rear end?”
Weebles are an elementary particle described be the Standard Model of physics. They are particularly notable due to several features. Weebles undergo what Heisenberg described as "quantum Weeble wobble." This does not sound extraordinary to a layperson, but there is a further feature of Weebles that is unique in the known universe. Though Weebles undergo constant wobble in all 13 dimensions, they do not fall down. This is seemingly contrary to Newton's Nth Law of Motion, which clearly states: "All ye objects who shall wobble will, most certainly and beyond a shadow of a doubt, fall down, indubitably."
Symmetry of the Weeble
Imagine you are standing on a train moving at 87.3% of the speed of light. The train is moving across the surface of a planet that is infinitesimally small (and therefore has no gravity) and the car you are on is rotating counterclockwise with respect to the vector of motion. Because you are far from home and spinning very quickly on a moving train, you would quickly become ill, puke, and fall down.
Now imagine that as you are falling, you look out the window and see a Weeble experiencing only slight quantum Weeble wobble. From your perspective, it should appear that the Weeble is not only wobbling but has, contrary to Newton's Nth Law, indeed fallen down. Since both you and the Weeble have equal claim in saying that you are standing still, the Weeble must concede that it is equally likely that it is the one who has fallen down, and not you.